One of the fundamental shortcomings of standard color photography systems is the relative nonpermanence of the resulting color prints. Even with high quality components, the life of the print is measurable in a rather finite number of years. Dye transfer techniques, on the other hand, are known and available which enable the truly permanent preservation of color photography reproductions. The dye transfer process involves the initial preparation of color separation plates, which are utilized in the preparation of the final color reproduction by means of printing procedures. The color separation plates themselves have great permanence and, for all practical purposes, may be preserved indefinitely (e.g. hundreds of years) and reused from time to time as desired.
As a practical matter, the dye transfer process has not been widely used by either professional or amateur photographers, because of the complicated, inconvenient and time-consuming procedures required in the preparation of the color separation plates. For example, prior to making of the color separation exposures, it is necessary to perform a series of test exposures, with varying exposure times, for each of three color separation filters. From these test results, performed with respect to each negative from which a dye transfer print is to be made, the photographer determines the optimum exposure time for each of the several filters, to be used in each of the several color separation exposures to be made. As will be readily apparent, this involves a succession of operations. Moreover, the exposures involved in the dye transfer procedures must be carried out in total darkness, without benefit of a subdued or filtered darkroom light of any kind. Accordingly, not only are the required operations large in number, but they are somewhat inconvenient to carry out, requiring the photographer to work in total darkness, strictly by feel.
Because of the time involvements and inconveniences, the dye transfer process has been largely ignored, notwithstanding other significant advantages in the process, particularly to the serious professional photographer.
In accordance with the invention, a novel and advantageous form of test exposure and printing easel is provided which greatly simplifies and expedites the necessary operations involved in the preparation of color separation plates for the dye transfer process, rendering the process significantly more attractive to use. The apparatus of the invention comprises a two-sided, reversible easel assembly which in one orientation serves as a test board, enabling a succession of exposures, with each of a plurality of different color separation filters, to be carried out rapidly, conveniently, and accurately under conditions of total darkness. In its reversed orientation, the easel assembly of the invention provides a support and reference plane for carrying out the final color separation exposures.
For a more complete understanding of the above and other features and advantages of the invention, reference should be made to the following detailed description of a preferred embodiment and to the accompanying drawings.